In the Garden:
Pacific Northwest
September, 2006
Regional Report

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I love getting a jump-start on spring by forcing daffodils indoors.

Forcing Bulbs for Indoor Bloom

September and October are prime months for purchasing spring-blooming bulbs. I always buy extra to pot up and force into early bloom indoors. Forcing bulbs is easy; it just takes a little advance planning.

How to Start Forcing Bulbs
The first step is to purchase fresh bulbs. Look for bulbs that are firm, uniform in size, and free of mold. The more familiar mainstays of spring -- including tulips, hyacinths, crocuses, and narcissus -- perform reliably when forced. If you're adventuresome, you can also try fritillaria, scilla, snowdrop, and winter aconite.

Once you've chosen your bulbs, gather together some decorative pots. Almost any pot will do, providing there's enough room for roots to develop. Pots with drainage holes and saucers are safest to use because they make it hard to drown the roots. You can also use pots with no drainage holes but you must water very carefully.

Ordinary potting soil retains moisture and provides air spaces for good root formation. You can buy it ready-made or mix your own. My recipe is one part peat moss, one part perlite, and one-half part sand. The sand adds enough weight to anchor the container and keep top-heavy bulbs, such as daffodils, from tipping over when in full bloom.

When you plant the bulbs, put them high in the pot and space them closely. I fill the pot three quarters full of potting mix, set the bulbs close together on top of the mix, and then add more mix to cover them. Spacing the bulbs 1 to 2 inches apart makes a good show of color, and the close spacing doesn't seem to bother them. I like to mix bulbs in a pot, but planting a single type, such as grape hyacinths, will produce a strong sweep of color which could be used as an accent in a collection of foliage houseplants.

Keep Them Cold
Your newly potted bulbs will need about three months of cold, moist conditions in order to develop healthy roots. The simplest way to accomplish this is to place the pots outdoors in a sheltered spot and cover them with a pile of leaves. A south or west wall might allow sunshine to reach the pots and heat them up too much, so I set mine in a group next to the north wall of my house. Tossing about a foot of dried leaves on top will help insulate them from the cold. I check periodically to make sure the soil remains moist but not soggy. I also mark my calendar so I'll know when to bring the containers in out of the cold.

Here Come the Blooms
When your bulbs have chilled for about three months, start checking their progress as indicated by their root growth. Don't be misled into thinking they're ready to be taken out of the cold by a shoot poking up through the potting mix. To be sure, lift each pot and look at the bottom. If you see plump, white roots poking through the drainage holes, the bulbs are ready to come in out of the cold. The timing varies from one kind of bulb to another; some bulbs need just three months of chilling while others may require four months.

When your bulbs are ready, bring them into a bright room. They need the light so their leaves and flower stems will grow short and sturdy. Weak light will produce tall and lanky flower stems that are likely to flop over. If you bring only a few containers in at a time, waiting 7 to 10 days before bringing in a few more, you'll have bulbs at varying stages of development. This will provide you with a steady display of blooms for several months.

Forcing seems to shorten the bloom time of most bulbs. For example, indoors, grape hyacinths remain fragrant and lovely for about a week. Outdoors, they last two to three weeks. I think the difference has to do with warm indoor temperatures. You can prolong their bloom by placing them in a cool place overnight and bringing them back into a bright room during the day.

Forced bulbs can be planted outdoors, but they never seem to perform well for me. I prefer to toss the bulbs and start all over with fresh bulbs each autumn.


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